The present invention is directed to cigarettes and other aerosol generating smoking articles which provide less than about 10 mg of carbon monoxide (CO) to the smoker, and to compact fuel elements useful in these articles. Cigarettes, cigars and pipes containing various forms of tobacco are the most popular forms of smoking products. Thus, as used herein, the term "smoking article" includes cigarettes, cigars, pipes, and other smoking products which generate an aerosol such as smoke.
Many smoking products and aerosol generating smoking articles have been proposed through the years as improvements upon, or as alternatives to, the popular forms of smoking products, especially cigarettes.
Some, for example, have proposed tobacco substitute smoking materials. See, for example, U.S. Pat. No. 4,079,742 to Rainer et al. Two such materials, Cytrel and NSM (New Smoking Material), were introduced in Europe in the 1970's as partial tobacco replacements, but did not realize any long-term commercial success.
Others have proposed smoking articles, especially cigarette smoking articles, based upon the generation of an aerosol or a vapor. See, for example, the background art cited in U.S. Pat. No. 4,714,082 to Banerjee et al.
As far as the present inventors are aware, none of the foregoing smoking articles has ever realized any commercial success, and none have ever been widely marketed. The absence of such smoking articles from the marketplace is believed to be due to a variety of reasons, including insufficient aerosol generation, both initially and over the life of the product, poor taste, off-taste due to thermal degradation of the aerosol forming and/or flavor generating materials, the presence of substantial pyrolysis products and sidestream smoke, and unusual or unsightly appearance of the articles themselves.
Thus, despite decades of interest and efforts, there is still no aerosol generating smoking article on the market which provides the benefits and advantages associated with cigarette smoking, without delivering considerable quantities of incomplete combustion and pyrolysis products.
More recently however, in Banerjee et al., supra. and in European Pat. Publication Nos. 0174645 and 0212234 to the R.J. Reynolds Tobacco Co., cigarettes and other aerosol generating smoking articles are described which are capable of providing the benefits and advantages associated with cigarette smoking, without delivering appreciable quantities of incomplete combustion and pyrolysis products and without many of the other drawbacks associated with previous aerosol generating smoking articles. The preferred cigarettes and other smoking articles of these publications are described as having small, preferably carbonaceous fuel elements, and a physically separate aerosol generating means. No indication is made regarding the amount of carbon monoxide delivered by those smoking articles.